Good morning folks, I am having some PH issues with my DWC and I really need someone with experience / knowledge to help me understand what the hell is going on. My DWC consists of a 10-gallon tub filled with 5 gallons of water. This DWC is supporting a single plant that has been growing strong for 12 weeks now. I just flipped the lights to flower yesterday. It seems that on a DAILY basis, my PH drops at least 1 to 1.5 full points and I'm having to add 1.5 to 3.0 MLs of PH-Up to the reservoir to get my PH back into an acceptable range. My water level does not drop that fast and my PPMs are staying stable. For example, not 20 hours ago, I took the following readings from my plant environment: - Air Temp: 64 - Water Temp: 62.7 - Humidity: 32% - Water PH: 6.0 - Water PPM: 590 This morning, I took the same readings: - Air Temp: 63 - Water Temp: 62.5 - Humidity: 30% - Water PH: 4.8 - Water PPM: 590 I had to add 3.0 MLs of PH-Up to get my reservoir PH back up to 6.1. My water level did not drop overnight and my PPMs remained the same at 590. I've been using 10ml of Hydroguard with every reservoir change and my roots look fine & bright. The water smells fine and there does not appear to be any signs of root rot. I've attached my feeding schedule and as I just flipped to flower yesterday, I changed my reservoir and followed the "Week 6 - Transition" nutrient levels at 1/3 strength. Can someone please help me understand why my PH is dropping like this on a daily basis? PLEASE HELP.